Motor operated mechanism



2 1940- .s. c. SHIPLEY Efr AL MOTOR OPERATED MEcHANIsM Filed Dec. 16,1957 3 Sheets-Sheet l /YIMUYlflJ/ A/ diz lvanus d. Shiple y Benjamin (yr(W W M 1940- s. c. SHIPLEY EI'AL MOT-OR OPERATED MECHANISM Filed Dec.16, 1937 3 Sheets-Sheet 2 m/Uf/Mfo m/ Sylvanzw C. Shipley Ben Jamln Cy)"W fi M 1940- s; c. SHIPLEY ET AL 2,222,990

MOTOR OPERATED MEGHANI SM Filed Dec. 16, 1937 s Sheets-Sheet 5 L- Ill Jylvanws U. Sh ipley Benjamin Cy)" W MM Patented Nov. 26, 1940 UNITEDSTATES PATENT OFFICE MOTOR OPERATED MECHANISIVI Application December 16,1937, Serial No. 180,179

Claims.

This invention relates to a motor operated mechanism and moreparticularly to one of the type wherein an element is biased to oneposition and is moved against its bias and held in a sec- 5 and positionby the continued energization of a motor.

In many arts, it becomes necessary to move a controlling element betweentwo positions, one of which is a safe position and the other of which isan active position. An example of such an element is a valve controllingthe flow of fuel to a burner. When the valve is closed, it is in a safeposition inasmuch as the continued maintenance of the valve in thatposition does riofoause I an unsafe condition to be created. When thevalve on the other hand is in open position, it is in an active butunsafe position inasmuch as if the valve continues in that position, theburner may cause an overheating of the device heated thereby. Anothersuch example of an element which is movable between a safe and an unsafeposition is an electric switch. Such a switch is often used to controlheating apparatus or apparatus whose continued operation under somecircumstances may be undesirable. Where such elements are controlled bypower operated devices, which in turn are controlled by automaticallyelectrically operated controlling systems, it becomes highly imperativethat some means be provided for insuring that these elements are movedto their safe position in the event of power failure. It is,accordingly, a common practice in certain arts to have the elementbiased towards a safe position and moved by an automatically controlledelectric motor to its active position, the biasing means being effectivein the event of power failure to return the element to its safepositionv An art in which this principle is used to a considerableextent is the valve art, particularly where the valves are used for thecontrol of a heat producing medium. In this case, the motor operatingthe valve is thermostatically controlled.

One very serious difliculty which has been encountered, however, in suchmotorized valves is that it is necessary to maintain the motorcontinually energized when the valve is in its open position. Thisresults in the motor heating up with the result that there is a tendencyfor the bearings to stick, Inasmuch as such a motor usually operates thevalve through a reduction gear train, any tendency of the motor tostick, no matter how slightly, offers a decided resistance to the returnof the valve by the spring. inasmuch as the spring, in order to returnthe valve, must rotate the entire gear train and motor, By reason of thefact that the motor is connected to the high speed end of the geartrain, it must be rotated at a relatively high speed. It is impossibleto overcome this difficulty by merely increasing 5 the tension of thespring since this in turn results in the necessity of a much largermotor, which in turn gives olT more heat when maintained in itsenergized position. As a result of this situation, considerable dimcultyhas been experienced in the past with valves of this type sticking inopen position and causing an excessively overheated condition, which incertain instances have resulted in fires.

'It will be readily apparent that the same difficulty would beexperienced in the operation of any element biased to a safe position bymeans of an electric motor.

An object of the present invention is to provide a device of this typewherein upon initial movement of the apparatus, in the reversedirection, the element is disconnected from the motor so that thebiasing means is able to return the element unimpeded by the motor.

A second object of the present invention is to provide means in such anarrangement to stop the return movement of the motor at a point suchthat sufficient lost motion will exist in the connecting means to insurethe establishment of a maintaining circuit during the taking up of such30 lost motion.

Further objects of the present invention will be apparentfromaconsideration of the accompanying specification, claims and drawings, ofwhich:

Figure 1 is a vertical sectional View of the motor operated mechanismtaken substantially along the line of Figure 2;

Figure 2 is an end elevational view of the same looking from the left inFigure 1 and showing the cover for the mechanism in section, the sectionbeing taken along the line 2-2 of Figure 1;

Figure 3 is a side elevational view looking from the right in Figure 2with certain portions being shown in section along the line 3-3 ofFigure 2 and with the terminal block and binding post being shown inbroken lines as though transparent;

Figure 4 is a diagrammatical view of the structure shown in Figures 1 to3 and including the electrical control system therefor, and

Figure 5 is a detailed view of a portion of the valve operatingmechanism in the position it assumes when the valve is in its openposition.

While the invention is not so limited, the same has been illustrated asapplied to the operation of a valve for controlling the now of gas to aburner.

Referring now to Figures 1 to 4, the control valve generally designatedat 9 has a valve casing l0 having outlet andinletopenirigs H and i2,respectively. The valve casing ID has a transverse wall l3 having a portopening it therein which is encompassed by an annular shoulder to form avalve seat l5. The valve member comprises a valve disc l6 adapted toseat on the annular seat l5, reinforcing washers i1 and i9 flanking thevalve disc I6, said valve disc I6 and said reinforcing washers i? and 59being securely clamped together by means ofa plug i9 and a nut 29screwed thereon,

Extending into theflpl s s J! of the valve member is a valve stem 2|,the plug l9 and the valve stem 2| having holes to receive a pin 22 tosecure the valve stem 2| and plug I! together in fixed relation. Mountedin an annular groove in the valve stem 2| is a split ring 23 whichsupports a spring retainer member 24. A spring 25 rests in the springretainer member 24 and abuts against an abutment plate 28 tar normallyurge the valve member toward its 1-; Located adjacent the upper portionof tho slve casing I0 are a disc 21, a packing washer 1.4. and a sup-=port 29 which are secured togei and to the abutment disc 26 by means oirivets 39. 3| designates a clamping nut, screw-threaded on the upperportion of the valve casing M to hold the support 29 in fixed relationto the valve casing I0.

Extending through the abutment disc 26, the disc 21, the washer 28, andthe support 29 and secured thereto is a sleeve guide member 32 throughwhich the valve stem 2| slida tends outwardly from the valve casingorder to effectively seal the valve i9 leakage of fluid therefrom adiaphragm is secured to the outer end of the valve stem 2| by clampingthe diaphragm 3"! between a nut 34 and a washer 35, the clamping actionbeing efiected by a nut 38 screwed on the screwthreaded portion 33 ofthe valve stem 2|. The outer edge of the diaphragm 31 is clamped cctweenthe support 29 and a base 39 by means of screws 39.

Mounted on the base 38 by means of screws 42 are two upright, spacedparallel plates 40 and 4|, the plates 40 and 4| being held in spacedrelation by bolts 43 cooperating with nuts 45 to clamp the plates 40 and4| against spacer mem bers 44.

A motor of any known type, generally designated at 45, is secured to andspaced from the vertical plate 40 by means of screws 41 and spacers 48.The motor shaft extends through the plate 40 and has a motor pinion 49located on the end thereof. Located between the plates 40 and 4| anddriven by the motor pinion 49 is a reduction gear train, comprising agear 59 engaging the motor pinion 49, a gear 52 engaging a pinion 5|integral with the gear 50 and a gear 54 engaging a pinion 53 integralwith the gear 52. The gears and pinions are suitably mounted and spacedbetween the upright parallel plates 40 and 4| by means of bearings 55.

By means of a pivot pin 59 and spacers 50, a lever 58 is pivoted betweenthe plates 40 and 4| and by means of a pivot pin 6| and spacers 92 thelever 58 is pivoted to a U-shaped bracket 63, which bracket 63 issecured to the valve stem 2| by a nut 64 screwed on the screw-threadedengages the pin 9|.

portion 33 of the valve stem 2| whereby movement or the lever 58 in aclockwise direction about its pivot pin 59 causes opening of the valve9.

A pawl member 66 is pivotally secured by means of a pivot pin 61 to thelever 58. This pawl member intermediate the length thereof is providedwith a shoulder portion 68 which is adapted to cooperate with a pin 69secured to plate 40. The pawl member 86 is biased into engagement withpin 69 by means of a spring 10 surrounding the pivot pin 61 andwhichengages at one end the pawl member and at its other end a pin'Hsecured to the lever 58. The pawl member 96 is also provided with ahook portion 12 at a point somewhat above the shoulder portion 68. Thishook portion 12 is designed to cooperate with a pin 14 carried by thegear 54- in the low speed end of the gear train. The upper end of thepawl member 66 is bent forwardly as at 15 and has pivotally securedthereto a member 16. This member is provided with a transverselyextending tooth engaging member ll, which under certain circumstancesengages the tooth of the gear so as to disengage the hook portion 12from pin id. The member 16 is provided at its outer end with a curvedextension 19 which is adapted to engage the fixed pin 43 to limitoutward movement of member '19 and consequently of pawl member 66.

Secured to pawl member 66, as best indicated in Figures 1 and 2,particularly the latter, is a spring member 89. This spring member isrig idly secured at its lower end to the pawl memher and is curved at 8|at its upper end. This curved upper and Bi of the spring member 89 isadapted to engage the pin 14 of gear 54 upon movement of the gear invalve closing direction.

The gear 54 is secured to a shaft 85. Also mounted on this shaft, asindicated in Figures 2 and -3, is a pair of collar members 86 and 81.

Collar member is rigidly secured to the shaft 85 whereas collar 81' isslidably but non-rotat ably secured thereto. A cam member 99 is locatedbetween the collar members 89 and 81. A spring 99 bears against thecollar member 81 and urges the same against the cam member 98 to clampthe same between collar members 86 and 8?. In this manner, cam member 88is frictionally connected to shaft 85 so as to rotate therewith when itsmotion is unimpeded. The cam member 89 is provided adjacent its upperportion with a notch 99 which is adapted to cooperate with a pin 9|secured to the plate 4|. The pin 9| effectively serves to limit themovement of cam 88. Thus upon rotation of the motor in either direction,cam 88 is initially rotated until a respective shoulder of the notch Thecam member 88 is employed for actuating a, maintaining switch. Thismaintaining switch consists of a fixed contact carrying member 93 and amovable contact carrying member 94. Movable contact carrying member 94is pivotally mounted to plate 4| at 95 and has attached thereto anelongated resilient member 96 which engages a pin 91 se cured to aterminal plate 33. This terminal plate 83, which in Figure 3 is shown asif transparent, is secured to plate 4| by screws 82 and spacers 94. Theresilient member 96 serves to bias contact carrying member 94 away fromfit) bers 93 and 94 are provided with contacts I00 and IN,"respectively, and upon the cam follower 98 engaging the toe portion 99of cam member 88, upon clockwise rotation of the cam member, contactsI00 and I01 are moved into engagement with. each other. The action ofthe maintaining switch is, accordingly, that upon initial movement ofthe motor in valve opening direction, contacts I00 and IIII are movedinto engagement with each other, and upon an initial movement of themotor in valve closing direction, the contacts I00 and IOI are separatedfrom each other. The function of this maintaining switch will be moreapparent from the subsequent description.

Surrounding the mechanism is a cover member I05. This cover memberslides over the edge of the base member 38 at its lower end and is heldin position at its upper edge by a bolt and nut assemblage secured toplate 40 and generally indicated by the reference numeral I08. Thiscover can be conveniently removed when desired by unscrewing the nut ofthe fastening means Hi8.

The lever 58 projects through the cover I05, as indicated in Figures 1and 3. The righthand portion thereof, as viewed in these figures,provided with a plurality of holes I08. These holes are for the purposeof attaching a chain, or similar member thereto, for operating a damperby means of lever 58. This function of t .maticaily illustrated. inFigure 4. While the primary purpose of lever 58 extending through thecover is to actuate a damper or othe the same time furnishes a means wemay be manually actuated in er failure. Inasmuch as it is oneinexperienced with the art operate the valve under such circumstances,the shoulder 58 is provided for the purpose preventing such opening ofthe valve without removal of cover I05, as will be explained in moredetail later. Upon removal of cover H15, shoulder 68 can be withdrawnfrom the path of pin 69 by engaging a thumb piece I H] on the pawlmember 68. When this is done, it is possible by hearing down on theright-hand end of the lever 58 to move the valve towards open position.A plunger member H2 is provided for the purpose of holding lever 58 inits valve open position when it is so moved manually. The plunger H2 isslidable in a bearing member H3 and is provided at its inner end with acollar member II4 which is designed to be moved into the path of lever58. A collar II5 of insulating material is secured to plunger II2.Extending between this collar H5 and a supporting plate 45 is a springIIG, which spring serves to bias plunger II2 to the position shown inFigure 2 wherein collar member H4 is out of the path of movement oflever 58. Secured to the terminal plate 83 is a fixed contact member H8.Cooperating with this contact member H8 is a movable contact member iI9. Movable contact member H9 is biased into engagement with fixedcontact member H8 but is normally prevented from moving into engagementwith contact member M8 by reason of the collar |I5 which is biased bythe spring IIIi. It will be noted that collar H5 is in engagement withcontact member Hi When the plunger is in. its normal position shown inFigure 2. The contact members H8 and H9 form the two contacts of a rauxiliary apparatus, extension recycling switch, as will be moreapparent from the subsequent description. I

In Figure 4, a portion of the apparatus is shown schematically togetherwith the control system for operation of the motor. The motor 46 isshown in the present figure as being of the shaded pole induction type.The motor comprises a stator core I25 upon which is located a fieldwinding I26. The core I25 is formed with the two pole portions I21 andI28 which are split. Opposite halves of the two pole portions areprovided with shading rings I29 and I30 of any conventionalconstruction. A rotor I3I of the conventional squirrel cage type isrotatably mounted between the pole portions I21 and I28.

A thermostat is shown as forming the controlling switch. This thermostatis indicated gen erally by the reference numeral I35. This thermostatconsists of a contact arm I38 which is secured to a bimetallic elementI31. The contact arm I38 is designed to engage fixed contacts I38 andI39. The contact I38 is spaced farther from contact arm I38 than contactmember I39. The result is that upon movement of contact arm I38 in thedirection of contacts I38 and I39, the contact I39 is engaged first.Simi larly, on movement of contact arm I36 in the opposite direction,the arm I38 separates first from contact I38. Bimetallic element I31 isarranged so that upon a temperature fall, the contact arm I38 is movedto the left.

Power is supplied for operation of the system by a step-down transformerI40. This transformer comprises a line voltage primary HI and a lowvoltage secondary I42. The line voltage primary I is connected to-linewires I43 and I44 leading to a suitable source of power (not shown). Aswitch comprising a switch blade I46 and a fixed contact I41 is providedfor manually interrupting the power supplied to the motor when it isdesired to place the valve out of operation for a considerable period oftime. I In this figure, the lever 58 is shown as connected to thesecondary air damper of a gas burner. This damper is for the purpose ofcontrolling the admission of secondary air to the burner. The damper isgenerally indicated by the reference numeral I50 and is pivoted to thecasing I5I surrounding the gas burner. Only a portion of this casing isshown in the drawing. A chain I52 is shown as extending between thedamped I50 and the lever 58.

The other elements of Figure 4 are shown schematically and correspond toelements shown and described in connection with Figures 1 to 3, andinasmuch as they bear the same reference characters as the correspondingelements in Figures 1 to 3, it is believed that a further description ofthese elements in connection with Figure 4 is unnecessary.

Operation Various elements are shown in the position which they occupywhen the thermostat I35 is in a position wherein it is not calling forthe valve to be opened. Where the valve controls the flow of gas to aburner. as in the present instance, this position of the thermostat willbe the position which it assumes when the tempera-- ture is above thedesired value. Let it be assumed now that the temperature begins to fallby reason of the valve being closed. This will cause movement of contactblade I35 to the left causing it to successively engage contacts I39 andI38. The engagement with contact I39 has blade I36. bimetallic As soon.however, as the engagement I38 is eifected, the following circuit noeffect. of contact is established: from the right-hand terminal ofsecondary I42 through conductor I55, contact I41, switch blade I46,conductor I56, conductor I51. contact I39, contact; arm I36, contactI38, conductors I58 and I59, field winding I26, and conductor I60 to theother terminal of secondary I42. The result of the establishment of thiscircuit is that the motor becomes energized causing gear 54 to berotated through the various elements of the gear train for reasons to besubsequently explained. The pin 14 at the time this movement is startedwill be in approximately the position indicated in solid lines in Figure4. The rotation of gear 54 which will take place in a clockwisedirection will result in the pin 14 similarly being moved in a clockwisedirection away from hook 12. It will be readily apparent that uponslightly less than 360 of revolution of gear 54, the same will bebrought into engagement with the under surface of the hook portion 12 ofpawl member 66. Before, however, such engagement of pin 14 with hookportion 12 occurs, the cam member 88 will be moved in a direction toclose contacts I00 and IOI, as previously explained. The engagement ofthese con- Iacts will result in a new circuit being established to fieldwinding I26 as follows: from the righthand terminal of secondary I40through conductor I55, contact I41, switch blade I46, conductor I56,conductor I51, contact I39, switch element I31, conductor I62, contactsIOI and I00, conductors I63, I64, and I59, field winding I26, andconductor I60 to the other terminal of secondary I42. It will be notedthat the last traced circuit is independent of contact I38. Thus, eventhough the temperature should rise slightly to cause disengagement ofswitch I36 with contact I38, the motor will not be stopped. It will thusbe seen that the temperature differential is required between thestopping and starting of the motor. In this manner, any chattering ofthe thermostat will not result in rapid energization and deenergizationof the motor.

As previously indicated, the continued rotation of gear 54 in aclockwise direction results in the engagement of pin 14 with the hookportion 12. As soon as such engagement takes place, further rotation ofgear 54 results in pawl member 66 being raised upwardly and moving thevalve towards open position. Due to the fact that the pin 14 follows anarcuate path, the pawl member 66 will be swung outwardly by the pin 14thus enabling shoulder 68 to clear the stop pin 69. The position of pawlmember 66 shortly after it passes pin 69 is shown in dotted lines inFigure 4. After shoulder 68 has thus cleared pin 69, the pawl member 66,the lever 58, and the valve will be free to continue to move upwardly.Such upward movement will continue until the lever 58 engages the pin69. at which time the various elements will assume the position shown insolid lines in Figure 5, which corresponds to open position of thevalve. The motor will be effective thereafter to conlinue to hold thevalve, or other actuated element, in its uppermost position. It is to beunderstood that the gas admitted by the valve to the burner is lightedby a pilot light, or some other conventional igniting means.

At the same time that the valve is moved to its open position, adownward movement of the right-hand end of the lever 58 results in secondary air damper I50 being moved to open position. It will be notedthat this damper is biased to open position so that as soon as the lowerend of lever 58 moves down, the weight of damper I50 is able to move thedamper to open position. The opening of the secondary air damper permitsair to be admitted to the burner to support combustion.

The continued admission of gas to the burner by reason of the valvebeing held in open position eventually results in the temperature towhich thermostat I is subjected rising to the point where the switchblade I36 separates not only from contact I38 but also from contact I39.

When this occurs, both circuits to the motor field I winding I26 areinterrupted so that the motor is completely deenergized. The biasingspring 25 is thereupon effective to rotate lever 58 and, through thepawl member 66, the gear train and the motor in the reverse directiontowards valve closed position. It will be noted that the under surfaceof tooth engaging member 11 is free of any sharp projections so that aslong as the gear 54 is rotating in clockwise direction, the toothengaging member 11. merely rides over the surfaceof the teeth. As soonas gear 54 starts to rotate in the reverse direction, the tooth engagingmember 11 engages the teeth of gear 54 so that member 16 andconsequently pawl member 66 are pushed to the left. It will be readilyapparent that after such movement of pawl member 66 to the leftcontinues for a relatively short distance, the hook portion 12 isdisengaged from pin member 14, as shown in dotted lines in Figure 5. Thedisengagement of hook portion 12 from pin 14 effectively interrupts theconnection between the valve and the motor and gear train. The result isthat the valve, the lever 58. and the pawl member 66 are free to movedownwardly independently of the gear train and motor. Moreover, suchreturn movement is accomplishedquite rapidly so as to insure an abruptclosing off of the gas to the burner.

Due to the fact that the gear train has some momentum imparted to it bythe relatively limited motion thereof before the hook 12 is disengagedfrom pin 14, the gear train and motor will contime to rotate after suchdisengagement. If it were possible for pin 14 to clear the upper edge ofhook member 12, pin 14 might well be left in a position to close to theunder side of hook portion 12 that upon energization of the motor theengagement of pin 14 with hook 12 would take place before a maintainingcircuit could be established by closure of contacts I00 and IOI.Moreover, if such rotation continues sufficiently far in acounter-clockwise direction, it might engage pawl member 66 at the upperend thereof and move pawl member 66 outwardly so that shoulder 68 clearsthe pin 69, whereupon it would be possible for someone to manually openthe valve without removal of the cover. In order to guard against eitherof these contingencies, the hook portion 12 is provided with an uppersurface which is slightly recessed, as indicated at I61. Moreover, thespring 80 is provided which. as previously stated, has a curved end 8I.Upon pin 14 rotating in a counter-clockwise direction after hook 12 hasbeen disengaged therefrom, the pin 14 first strikes the spring 80. Theeffect of this spring is to yieldably halt further movement,

of the gear. In the majority of cases, pin 14 will never move intoengagement with the upper surface of hook portion 12. However, if itdoes, it

engages the same and moves downwardly into the recess portion I61 sothat any further movement thereof is effectively retarded. In tinsmanner, it is assured that a substantial movement of the gear 54 isnecessary upon reenergization of the motor before the pin I4 againengages the under side of the hook portion I2.

The amount of movement of gear 54 in the reverse direction which isrequired to move hook member I2, off of pin I4 is so slight that even ifmotor 46 has a decided tendency to stick, the chances are that suchmovement will still take place. Thus, the motor bearings may besufliciently sticky that the valve would otherwise creep back a certaindistance, and then by reason of the fact that the spring 25 would beunder less tension, such movement of the valve would be stoppedentirely. With the present invention, it is necessary to have only asmall amount of such movement before the valve is disengaged entirelyfrom the motor to assure closing of the valve. Due to the fact thatspring 25 is most highly compressed when the valve is in fully openposition, the probability is very great that a small amount of suchmovement will take place.

As previously indicated, it is considered undesirable in many instancesfor the average user to be able to manually open the valve by merelygrasping the right-hand end of lever 58 and moving the same downwardly.For this reason, the shoulder 68 is provided which, if an attempt ismade to open the valve in this manner, will engage pin 69 to preventsuch movement. The service man or other person skilled in the operationof the equipment, however, can manually open the valve by merelyremoving the cover I85. When the cover is removed, it is possible tomanipulate the thumb piece I ID to swing the pawl 66 to the left andmove shoulder 68 out of the o path of pin 69. It is then possible tomove the valve to open position by depressing the righthand end of lever58.

The outer portion of member I6 is curved outwardly as at I8, aspreviously indicated. This outwardly curved portion is designed toengage with pin 43 so that when thumb piece I I8 is manuallymanipulated, there is no danger of pawl 66 being moved so far to theleft that the toothed follower II of member I6 rides off of the gear and50 drops down on the left-hand side of the gear.

lever 58 in valve open position, the contact members I I8 and I I9 aremoved into engagement. As previously indicated, these contactsconstitute a recycling switch. The purpose of this is to insure that thevalve is again placed under control of the thermostat as soon as poweris restored. Closure of these contact members I I3 and I I9, as bestindicated in Figure 4, results, as soon as power is restored, in thefollowing energizing circuit to the field winding I26: from theright-hand 70 terminal of secondary I42 through conductor I55,

contact I41, switch blade I46, conductor I56, conductor I10, contactmembers H8 and H9, conductors III, I64,and I59, field winding I26, andconductor I60 to the other terminal of secondary 75 I42. It will benoted that the circuit just traced is independent of the thermostat soas to insure that this circuit will be established immediately upon therestoration of power. While the position which the valve assumes whenmanually moved towards open position and held in this position by theplunger II2 has been previously referred to as the valve open position,this position is not the same as the complete valve open position towhich the valve is moved by the motor. In other words, plunger I I2 isdesigned to hold the left-hand end of lever 58 in a position where it isnot entirely in engagement with pin 69. Accordingly, as soon as themotor is reenergized, the gear 54 is rotated so as to cause reengagementof pin I4 with book portion I2 of the pawl member 66. The continuedrotation of gear member 64 causes the lever 58 to be moved to the fullopen position shown in. Figure 5. When this occurs, lever 58 is movedaway from the collar member II4 so that plunger H2 is free to move toits normal position through the action of biasing spring H6. Themovement of plunger I I2 to the right results in a separation of contactmembers H8 and H8 so that the circuit last traced to motor field windingI26 is interrupted. The motor is thereupon again under the sole controlof thermostat I85 and either stays energized or becomes deenergized,depending upon the then position of the thermostat.

It will be seen that the present invention provides an improved means ofinsuring the closing of a valve or other element biased to a safeposition upon deenergization oi the actuating motor, even though themotor or associated connecting elements offer such resistance to turningthat the biasing means would not normally be able to completely move theoperated element to its safe position. By reason of the device of thepresent invention, it is accordingly possible to obtain the advantagesof a device which is biased to a safe position and moved to anotherposition and held there only upon the continued energization of theactuating means and at the same time avoid the disadvantage thereofarising from the tendency of such mechanisms not to return to their safeposition upon the deenergization of the actuating means.

While a specific embodiment of the invention has been shown for purposesof illustration, it is to be understood that the invention is limitedonly by the scope of the appended claims.

We claim as our invention:

1. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, connecting means between saidmotor means and said element, said motor means being operative uponcontinued energization of said motor means to move said element towardand hold the same in said active second position, said biasing meansbeing operative upon deenergization of said motor means to move saidelement, said connecting means, and said motor in the reverse directiontoward said first position, and means operative in response to suchmovement toward said first position to render said connecting meansinoperative, said last mentioned means being actuable by energy of saidbiasing means whereby said element is returned by said biasing means tosaid safe first position independently of said motor means.

2. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, a reduction gear train having itshigh speed end connected to said motor means, connecting means betweenthe low speed end of said reduction gear train and said element, saidmotor means being operative upon continued energization of said motormeans to move said element toward and hold the same in said activesecond position, said biasing means being operative upon deenergizationof said motor means to move said element, said connecting means, saidgear train, and said motor in the reverse direction toward said firstposition, and means actuable by such movement toward said first positionto render said connecting means inoperative whereby said element isreturned by said biasing means to said safe first position independentlyof said motor means and said gear train.

3. In combination, an element to be operated movable between a. safefirst and anactive second position, means biasing said element towardsaid safe first position, motor means, connecting means between saidmotor means and said element, said connecting means comprisingcooperating pin and hook members, one connected to said element and theother actuated by said motor means, said motor means being operativeupon continued energization of said motor means to move said elementtoward and hold the same in said active second position, said biasingmeans being operative upon deenergization of said motor means to movesaid element, said connecting means, and said motor in the reversedirection toward said firstposition, and means responsive to suchmovement toward said first position to disengage said hook and pinmembers whereby said element is returned by said biasing means to saidsafe first position independently of said motor means.

4. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, a reduction gear train having itshigh speed end connected to said motor means, connecting means betweensaid motor means and said element, said connecting means comprisingcooperating pin and hook members, said hook member being connected tosaid element and said pin member being secured to the gear at the lowspeed end of said gear train, said motor means being operative uponcontinued energize-tion of said motor means to move said element towardand hold the same in said active second position, said biasing meansbeing operative upon deenergization of said motor means to move saidelement, said connecting means, said gear train, and said motor in thereverse direction toward said first position, and means operative inresponse to such movement toward said first position to disengage saidhook member from said pin member whereby said element is returned bysaid biasing means to said safe first position independently of saidmotor means and said gear train.

5. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, a reduction gear train having itshigh speed end connected to said motor means, connecting means betweenthe low speed end of said reduction gear train and said element, saidmotor means being operative upon continued energization of said motormeans to move said element toward and hold the same in said activesecond position, said biasing means being operative upon deenergizationof 75 said motor means to move said element, said connecting means, saidgear train, and said motor in the reverse direction toward said firstposition, and means operated by said gear train in response to movementthereof in the reverse direction to render said connecting meansinoperative whereby said element is returned by said biasing means tosaid safe first position independently of said motor means and said geartrain.

6. In combination, an element to be operated 1 movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, a reduction gear train having itshigh speed end connected to said motor means, connecting means betweensaid 15 motor means and said element, said connecting means comprisingcooperating pin and hook members, said hook member beingconnected tosaid element and said pin member being secured to the gear at the lowspeed end of said gear train, said motor means being operative uponcontinued energization of said motor means to move said element towardand hold the same in said active second position, said biasing meansbeing operative upon deenergizatlon of said inc- 5 tor means to movesaid element, said connecting means, said gear train, and said motor inthe reverse direction toward said first position, and means associatedwith said hook member, engaging an element of said gear train, and oper-30 ative in response to movement of said gear train in the reversedirection to disengage said hook member from said pin member wherebysaid element is returned by said biasing means to said safe firstposition independently of said 33 tor means, said motor means beingoperative 45 upon continued energization of said motor means to movesaid element toward and hold the same in said active second position,said biasing means being operative upon deenergization of said motormeans to move said element, said connecting means, and said motor in thereverse direction toward said first position, and means responsive tosuch movement toward said first position to disengage said hook and pinmembers whereby said element is returned by said biasing means 55 tosaid safe first position independently of said motor means, and meansfor yieldablylimiting the coasting of said motor and said gear trainafter said connecting means has been rendered inoperative.

8. In combination, an element to be operated movable between a first anda second position, means biasing said element toward said firstposition, rotary electrical motor means, a reduction gear train havingits high speed end con- 65 nected to said motor means, connecting meansbetween said element and said gear train, said connecting meanscomprising a first member carried by said gear train at the low speedend thereof and a second member connected to said 0 element and lying inthe path of said first member when said gear train is rotated by reasonof the energization of said motor, a control switch including a pair ofinsecurely engageablecontacts, a maintaining switch movable to closedcircuit means operative upon engagement of said pair of contacts of saidcontrol switch to cause energization of said motor, second circuit meansoperative upon closure of said maintaining switch to establish a circuitto said motor independently of said pair of contacts, said motor meansbein operative upon continued energization of said motor means to movesaid element toward and hold the same in said second position, saidbiasing means being operative upon deenergization of said motor means tomove said element, said connecting means, said gear train and said motorin the reverse direction toward said first position, means operative inresponse to movement of said motor in the reverse direction by saidbiasing means to render said connecting means temporarily ineffectivewhereby said element is returned by said biasing means to said firstposition independently of said motor means, and means for terminatingthe coasting movement of said gear train before thefirst member of saidconnecting means carried thereby is in a position where forward movementthereof would cause immediate engagement of the second member of saidconnecting means therewith whereby it is necessary for a sufllcientlylarge movement of said motor and gear train to take place beforeengagement of said members of said connecting means that the closure ofsaid maintaining switch is assured prior to the engagement of saidmembers.

9. In combination, an element to be operated movable between a first anda second position, means biasing said element toward said firstposition, rotary electrical motor means, a reduction gear train havingits high speed end connected to said motor means, connecting meansbetween said element and said gear train, said connecting meanscomprising a first member carried by said .g'ear train at the low speedend thereof and a second member connected to said element and lying inthe path of said first member whens'aid gear train is rotated by rea-'switch to establish a circuit, to said motor independently of said pairof contacts, said motor its means being operative upon continuedenergization of said motor means to move said element toward and holdthe same in said second position, said biasing means being operativeupon deenergization of said motor means to move said element, saidconnecting means, said gear train and said motor in the reversedirection toward said first position, means operative in response tomovement of said motor in the reverse direction by said biasing means torender said connecting means'temporarily ineffective whereby saidelement is returned by said biasing means to said first positionindependently of said motor means, and means for terminating thecoasting movement of said gear train at a point such that the twomembers of the connecting means are in a relative position such thatsufficient movement of the motor and gear train is required uponreenergization thereof before reengagement of said members to insure theclosure of said maintaining switch before such reengagement.

10. In combination, an element to be operated movable between a firstand a second position, means biasing said element toward said firstposition, electrical motor means, connecting means between said elementandv said motor means, said connecting means comprising interengagingmembers, one driven by said motor means and the other connected to saidelement,

' a control switch including a pair of insecurely engageable contacts, amaintaining switch movable to closed position upon initial movement ofsaid motor, circuit means operative upon engagement of said pair ofcontacts of said control switch to cause energization of said motor,second circuit means operative upon closure of said maintaining switchto establish a circuit to said motor independently of said pair ofcontacts, said motor means being operative upon continued energizationof said motor means to move said element toward and hold the same insaid second position, said biasing means being operative upondeenerglzation of said motor means to move said element, said connectingmeans, and said motor in the reverse direction toward said firstposition, means operative in response to movement of said motor in thereverse direction by said biasing means to render said connecting meanstemporarily ineffective whereby said element is returned by said biasingmeans to said first position independently of said motor means, andmeans for terminating the return movement of said motor at such a pointthat the two members of the connecting means are in a relative positionsuch that sufiicient movement of the motor is required uponreenergization thereof before reengagement of said members to insure theclosure of said maintaining switch before such reengagement.

11. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, connecting means between saidmotor means and said element, said motor means being operative uponcontinued energization of said motor means to move said element towardand hold the same in said active second position, said biasing meansbeing capable upon deenergization of said motor means of moving saidelement, said connecting means, and said motor means in the reversedirection toward said first position, and means operative as a result ofthe deenergization of said motor means to render said connecting meansinoperative whereby said element is returned by said biasing means tosaid safe first position independently of said motor means, said meansoperative as a result of the deenergization of said motor means being soconstructed and arranged as to utilize the force of said biasing meansto render said connecting means inoperative,

12. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, a reduction gear train having itshigh speed end connected to said motor means, connecting means betweenthe low speed end of said reduction gear train and said element, saidmotor means being operative upon continued energization of said motormeans to move said element toward and hold: the same in said activesecond position, said biasing means being capable upon deenerglzation ofsaid motor means of moving said element, said connecting means, saidgear train, and said motor in the reverse direction toward said firstposition, and

means actuable by energy of said biasing means upon deenergization ofsaid motor to render said connecting means inoperative whereby saidelement is returned by said biasing means to said safe first positionindependently of said motor means and said gear train.

13. In combination, an element tobe operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, disengageable connecting meansbetween said motor means and said element, said motor meansbeingoperative upon continued energization of said motor means to move saidelement toward and hold the same in said active second position, saidbiasing means being operative upon deenergization of said motor means tomove said element, said connecting means, and said, motor in the reversedirection toward said first position, andmeans actuable by such movementtoward said first position to disengage said connecting means wherebysaid element is returned by'said biasing means to said safe firstposition independently of said motor means and gear train.

14. In combination, an element to be operated movable between a safefirst and an active second position, means biasing said element towardsaid safe first position, motor means, connecting means between saidmotor means and said element, said motor means being operative uponcontinued energization thereof to move said element to said activesecond position, said biasing means being operative to move said motormeans, said connecting means, and said element in reverse direction whensaid motor means is denergized in a manner to impart momentum to saidmotor means, said connecting means being of a 5 one-way type permittingfreedom 01' movement of said motor means in reverse direction and meansarranged to resist and limit the amount of movement of said motor meansin reverse direction, said last mentioned means being ineflective toresist movement of said element, connecting means and motor means towardsaid safe first position.

15 In combination; an element to be operated means including saidbiasing means for returning said element to said safe first position,and

means operative in response to the initiation of such movement towardsaid first position to release said transmission means whereby saidelement is returned by said biasing means tosaid saie first positionindependently of said transso mission means.

SYLVANUS C. SHIRLEY, BENJAMIN CYR.

